Microsoft Issues Hotfix To Put The Pep Back In Internet Explorer's Step
"After you apply the MS14-037 or MS14-051 cumulative security update for Internet Explorer, web applications that implement consecutive modal dialog boxes may cause Internet Explorer to become slow and unresponsive over time. This issue occurs in Internet Explorer versions 7 through 11," Microsoft explains.
Even if IE hasn't become sluggish, you can check to see if you're at risk of a future slowdown in performance. Just load up the Control Panel, hit the System and Security section, then click on View update history under the Windows Update heading.
Sorting by name is probably the easiest way to proceed. Either way, the pair of patches you're looking for include KB2962872 and KB2976627. If you have one or both installed -- and you likely will if you have Windows configured to automatically update itself -- then you're a candidate for the hotfix.
There are several hotfix packages available, though you only need to install one, depending on which version of IE you have installed and which version of Windows you're running. You can find out more details (and grab your hotfix) here.